Opponents of Arizona's new immigration enforcement law protest outside the state capitol building in Phoenix, Arizona, Sunday. Critics of the law say that it will encourage racial profiling by law enforcement and endanger civil rights in the state.

Washington — As the Obama administration considers a potential legal challenge to Arizona’s tough new immigration law, a professor who helped draft the bill is defending the state measure as supportive of existing federal statutes.

Will the law lead to racial profiling?

Supporters say it is a necessary get-tough measure by Arizona officials in the face of ineffective federal enforcement efforts along the violent and lawless border with Mexico. They deny it will lead to civil liberties violations.

Last week, President Obama called the Arizona law “misguided,” and instructed administration lawyers to “examine the civil rights and other implications.”

Holder voiced similar concerns. He said the measure was “unfortunate” in that it might give rise to potential “abuse” by law enforcement officials. He declined to offer a more detailed legal analysis of the law’s ability to survive a constitutional lawsuit.

“We are reviewing the law right now,” the attorney general said. “We have a group that has been together over the past few days to examine exactly what our reaction is going to be.”

“What happened in Arizona is that good people are so afraid of an out-of-control border that they had to resort to a law that I think is unconstitutional,” he said during a hearing with Homeland Security chief and former Arizona Governor Janet Napolitano.

Napolitano told the Judiciary Committee she had deep concerns about the law from a law enforcement perspective. “We believe it will detract from and siphon resources that we need to focus on those in the country illegally who are committing the most serious crimes,” she said.

Later Napolitano, who is considered a potential nominee to the Supreme Court, was asked whether the Arizona law would pass constitutional muster. She declined to offer an opinion.

One key issue is whether the law seeks to unconstitutionally pre-empt federal immigration laws. Under the Constitution, federal law is the supreme law of the land and states may not pass laws that seek to overshadow federal statutes.

Professor Kobach said the Arizona law is supportive of federal immigration laws rather than seeking to supplant them.

“The bill adheres to the doctrine of concurrent enforcement – the legal principle that preemption will not be found where a state law prohibits conduct that is already prohibited under federal law,” he said.

'Reasonable suspicion'

The most criticized aspect of the Arizona law is a mandate in Section II that state and local law enforcement officials must verify a person’s immigration status “where reasonable suspicion exists that the person is an alien who is unlawfully present in the United States.”

It is this section that has drawn the harshest criticism, including allegations that it will authorize racial profiling.

Kobach said the Arizona law itself bars officers from relying on illegal factors like race, color, or ethnicity in making reasonable suspicion determinations.

One likely scenario

He offered an example of a likely scenario faced by local officials: An Arizona police officer stops a van driving erratically in a remote area known as an alien smuggling corridor.

“You might have a vehicle overloaded, no one in the vehicle has any identification whatsoever. The driver of the vehicle is acting evasively and trying not to answer the officer’s questions, perhaps one person in the vehicle concedes that he is unlawfully present [in the US],” Kobach said.

“At that point the officer would have reasonable suspicion that the other occupants in the vehicle are unlawfully present [in the US], and at that point this law requires the officer to [contact a 24-hour federal immigration hotline] to verify whether the individuals are lawfully or unlawfully present in the country,” he said.

Kobach said mere failure to have a driver’s license is not reasonable suspicion under the Arizona law. “It is two or more of these individual factors, then the totality of circumstances exist” to authorize the federal contact, he said.